The Winter Solstice occurs exactly when the earth’s axial tilt is farthest away from the sun at its maximum of 23° 26′. Though the Winter Solstice lasts an instant in time, the term is also used colloquially to refer to the day on which it occurs. For most people in the high latitudes this is commonly known as the shortest day and the sun’s daily maximum position in the sky is the lowest. The seasonal significance of the Winter Solstice is in the reversal of the gradual lengthening of nights and shortening of days.
In other words, it only gets warmer and lighter from this point forward!